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Algae and Microinvertebrates

Algae and Microinvertebrates. ENVIRON 311 / EEB 320 Winter 2006. Habitat & Communities. Phytoplankton. Phytoplankton – microscopic plants and some types of bacteria which obtain their energy via photosynthesis. Important to the ecosystem because Part of the primary producing community

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Algae and Microinvertebrates

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  1. Algae and Microinvertebrates ENVIRON 311 / EEB 320 Winter 2006

  2. Habitat & Communities

  3. Phytoplankton • Phytoplankton – microscopic plants and some types of bacteria which obtain their energy via photosynthesis. • Important to the ecosystem because • Part of the primary producing community • Assist in recycling elements such as carbon and sulfur which are required elsewhere in the community.

  4. Phytoplankton • Basis for aquatic food chain • Huge impact on global primary production • Estimated at 105 – 106 g C/year • More abundant in well-lighted areas with higher temperatures • Relatively unspecialized physiology, but are evolved to maintain buoyancy • Very little competitive exclusion • May be unicellular or multicellular

  5. Phytoplankton • Asexual reproduction keep numbers high • Cyanobacteria can double several times/day • Diatoms are slower, but can double every 1-2 weeks

  6. Phytoplankton • Phylogenetically diverse • Important groups: • cyanobacteria • dinoflagellates • euglenoids • green algae • diatoms

  7. Cyanobacteria

  8. Dinoflagellates

  9. Euglena

  10. Diatoms Gyrosigma obtusatum Pleurosira laevis Nitzschia levidensis

  11. Spirogyra(Genus of Green Algae)

  12. Lentic Zones

  13. Lotic Environments

  14. Lotic Environments

  15. Community Descriptions • Neuston – organisms floating in surface film of water • Pleuston – organisms living at thin air-water interface (bodies project into air) • Periphyton – organisms living attached underwater surfaces

  16. Periphyton • Sessile organisms, such as algae and small crustaceans, that live attached to surfaces projecting from the bottom of a freshwater aquatic environment. • Major groups include: • cyanobacteria • diatoms • filamentous green algae

  17. Cyanophyta Chlorophyta Euglenophyta Heterokontophyta Xanthophyceae Chrysophyceae Bacillariophyceae Phaeophyceae Rhodophyta Pyrrhophyta Oomycetes Cnidaria/Coelenterata Rotifera Ectoprocta/Bryozoa Hydrozoa Eucopepoda Cladocera Acari Algae and Microinverts

  18. Blue-Green Algae • Phylum Cyanophyta • Habitat: widespread in marine and fresh water • Notes: • Prokaryotic; no nuclear membrane or organelles • Lacks cellulose cell walls and flagella • Uses chlorophyll A, biliproteins, and carotenoids • May be colonial, filamentous, unicellular • Moves by extruding mucus

  19. Blue-Green Algae • Heterocysts fix N2 from atmosphere

  20. Green Algae • Phylum Chlorophyta • Habitat: widespread in marine and fresh water • Notes: • Very diverse group, hard to generalize about their ecology • May be unicellular, filamentous or colonial

  21. Green Algae Notes: • Cell walls of cellulose and nuclear membrane present • May possess 2 or 4 flagella

  22. Green Algae • Notes: • Utilize cholorphyll A/B and carotenoids • Store energy as starch • Some forms are large (e.g. Chara spp.) and at first glance resemble a higher plant

  23. Green Algae • Notes: • Some are good indicators of either nutrient rich (Cladophora spp.) or poor (Desmidae) environments

  24. Euglenoids • Phylum Euglenophyta • Habitat: freshwater • Notes: • Mostly unicellular with 1-3 flagella • Nuclear membrane but no cell walls

  25. Euglenoids Notes: • Found mostly in still water • Can be auto- or heterotrophic • Abundance of heterotrophic forms may be indicative of pollution

  26. Phylum Heterokontophyta • Algae having chlorophyll a and usually c, and flagella of unequal lengths • Terminology supersedes Chrysophyta in some classifications • Classes • Xanthophyceae • Chrysophyceae • Bacillariophyceae • Phaeophyceae

  27. Yellow-Green Algae • Class Xanthophyceae • Habitat: Primarily in freshwater, but some marine. • Abundance: Not abundant • Notes: Contains chlorophyll c (NO chlpyll b)

  28. Golden Algae • Class Chrysophyceae • Habitat: fresh water • Notes: • With or without chloroplasts; chloroplast yellowish green or yellowish brown due to a large amount of beta carotin and xanthophyll, also contains chlorophyll a and c • Facultative heterotrophs (in the absence of light)

  29. Diatoms • Habitat: Marine & freshwater • Notes: • ~20-25% of all organic carbon fixation carried out by diatoms • Single celled • Produces a frustule made of silica. • Bilateral symmetry • Radial symmetry Class Bacillariophyceae

  30. Diatoms: Order Centrales • Characterized by centric and often circular form • Note also the numerous punctae (pores)

  31. Diatoms: Order Pennales • Usually elongate • Characterized by numerous striae (grooves) that may run both parallel and perpendicular to the axis of the organism

  32. Brown Algae • Class Phaeophyceae • Habitat: mostly marine and littoral eukaryotic algae • Notes: • Some of the kelps can grow to enormous sizes, forming “kelp forests,” and hosting a unique fauna • Multicellular • Contains slimy mucilaginous materials

  33. Water Molds • Class Oomycota “Egg fungus” • Habitat: Freshwater • Notes: • Does not contain chlorophyll • Are heterotrophic • Produces gametes • Cell wall composed of a mix of cellulosic compounds • Nuclei are diploid (not haploid as in fungi) End Phylum Heterokontophyta

  34. Red Algae • Phylum Rhodophyta • Habitat: primarily marine but some fw • Notes: • Uses Chlor A/D, carotenoids and biliproteins • No flagellated life stage • Able to photosynthesize at very low light levels and wide range of the spectrum

  35. Red Algae Notes: • In MI, found in bogs/attached to logs in streams—can be locally common

  36. Dinoflagellates • Phylum Pyrrhophyta “Whirling flagella” • Habitat: Mostly marine, some freshwater • Notes: • Unicellular protists • 2 dissimilar flagella • Many are photosynthetic

  37. Dinoflagellates Notes: • Heterotrophic dinoflag feed on diatoms or other protists • Marine “blooms” • Red tides

  38. Rotifers • Phylum Rotifera “Rotating wheel” • Habitat: Fresh water • Notes: • Heterotrophic • Corona of cilia provide movement and means to move food toward the mouth.

  39. Rotifers Notes: • Sessile, anchors itself with foot • May enter dormancy and form cyst when env. conditions unfavorable • Cysts last up to 50 years

  40. Bryozoa • Phylum Ectoprocta (=Bryozoa) • “Moss animals” • Habitat: Marine and both lotic/lentic freshwaters • Notes: • Sessile; can be epiphytic, epilithic or epidendric • Colonial; a number of clones inhabit one structure • Extend ciliated tentacles to filter food from water • Often host a number of smaller organisms

  41. Cladocera • Phylum Arthropoda, Subphylum Crustacea, Suborder Cladocera • Water fleas • Habitat: widespread; very important in lentic habitats • Notes: • Uses antennae to swim • Many populations react to diurnal cycles, making vertical migrations each day • May be predacious or herbivorous • Head varies considerably from rounded to hooded but eye spot is always distinctive • Body laterally compressed

  42. Cladocera • Notes • Parthenogenetic: • most eggs are diploid females (asexual repro) • occasional diploid males fertilize haploid eggs produced by females for sexual reproduction

  43. Copepods • Phylum Arthropoda, Subphylum Crustacea, Subclass Copepoda • Habitat: widespread in marine and fw; may be benthic or pelagic • Notes: • may be parasitic, predacious or detrivorous • often seen carrying egg sacs on both sides • develop through several stages as nauplii before reaching maturity • Characterized by conspicuous 1st pair of antennae and single anterior eye

  44. Acari (Water Mites) • Phylum Arthropoda, Superclass Arachnida, Order Acari • Habitat: most abundant in lotic waters • Notes: • Have 6 legs when young, 8 when mature • Many are parasitic but a few are predaceous • Possess no antennae • Related to terrestrial spiders

  45. The End

  46. Phylum Cnidaria/Coelentaria • Corals, hydroids, sea anemones, & jellyfish • Habitat: Marine, freshwater (Hydra) • Notes: • Radial symmetry • Nematocysts • Two staged life cycle • Polyp (“juvenile”) • Medusa (“adult”) • Symbiosis w/plants in corals.

  47. Phylum Cnidaria/Coelentaria Notes: • Freshwater ecosystems: Hydra

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